Pumps are available that pump multiple fluids that are delivered in metered amount for precise mixing. Pumps that deliver a resin that receive a metered amount of catalyst are of this type. They are often in pumping systems that have a main and auxiliary pump in a master/slave arrangement. Precise metering of the amount of catalyst for mixing with the resin is necessary.
Precision metering is important for manufacturing of quality products. In the fiberglass reinforced product (FRP) industry the proper ratio of catalyst to resin is essential to proper curing of the finished product. This ratio is not fixed, however. Temperature, humidity and product varfiations can change the rate needed to achieve the desired result. Thus the changes needed in the ratio require adjustments over a predetermined range to allow for varying conditions as well as variations in the product itself. Adjusting the ratio while maintaining the precision metering needed is a prime objective.
One such metered proportional pumping system is shown and described in U.S. Pat. No. 3,650,434 of Johnson et al issued Mar. 21, 1972. This patent describes a metered primary fluid and a wobble plate that changes the stroke of pistons to vary the output of secondary fluid. A manual control varies the tilt of the wobble plate to vary the proportion of secondary fluid to primary fluid. While this device is effective it is complicated in construction and requires numerous parts. Also if any one of the pistons fail for any reason the ratio of secondary fluid to primary fluid will be immediately significantly affected and can cause damage to the product.
Other master/slave pump systems arrangements presently available have a small volume pump linked to the main pump by a long arm in a teeter-totter arrangement. Adjustments are made by mechanically disconnecting and re-attaching the auxiliary pump drive arm to the linking arm. This varies the mechanical linkage to shorten or lengthen the pumping link arm. This is not very precise or convenient. The link arm is provided with a series of holes for bolting the slave pump to operate in conjunction with the master pump. The slave pump is disconnected and rebolted at a selected position on the link arm to vary the slave pump stroke and adjust the output. However the adjustment then becomes incremental and not very precise.
Priming the auxiliary pump is also not convenient. The slave pump must be disconnected from the link arm and the stroke arm operated manually. This can also be hazardous as toxic materials have sometimes been sprayed on the operator.
The manual priming problem is particularly acute where toxic or hazardous materials are being pumped. Leaks have caused operators to be squirted with hazardous, toxic materials. This can be particularly dangerous if the operator or employee is squirted in the eyes with any of these hazardous materials.
The imprecise adjustment of the ratio of secondary fluid to primary fluid makes it difficult to determine the percentage of auxiliary fluid being delivered. It can then become a trial and error method to get the correct mixture, which results in waste of materials and is only approximate. This is because most present adjustment methods are not continuously adjusted over a selected range but has a number of incremental adjustments.
The present systems also use gravity feed to couple a single slave pump for spraying of primary and secondary fluids. This means that fluid must be poured in a reservoir for gravity flow and can result in contamination of the fluid. Thus the present system can only couple a single slave pump to pump a single secondary fluid with a primary fluid from a main pump.
It is one object of the present invention to provide a multiple fluid pumping system for primary and auxiliary fluids that have accurate, precise metering.
Another object of the present invention is to provide a continuously variable metering system for a multiple fluid pumping system.
Still another object of the present invention is to provide a precision metering system for pumping a secondary fluid in unison with a primary fluid that allow accurate prediction of the percentage of secondary fluid delivered.
Yet another object of the present invention is to provide a precision metered multiple fluid pumping system for multiple fluids in which the slave pump is directly driven from the main pump drive shaft providing continuous pumping of the secondary fluid without any free play or backlash.
Another object of the present invention is to provide a multiple fluid pumping system that pumps primary and secondary fluids that allows rapid, accurate adjustment of the delivery of the secondary fluid.
Still another object of the present invention is to provide a master/slave multiple fluid pumping system that allows the slave pump to be easily disengaged for priming either pump independent of the other.
Yet another object of the present invention is to provide a master/slave multiple fluid pumping system that permits pumping of a secondary fluid directly from the shipping container by suction feeding.
Another object of the present invention is to provide a master/slave multiple fluid pumping system that provides leak protection.
Yet another object of the present invention is to provide a master/slave multiple fluid pumping system that provides leak detection to indicate when seals need repair or replacement.
Another object of the present invention is to permit pumping of multiple secondary fluids from a master/slave multiple fluid pumping system.